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From: Marcus Weseloh <mweseloh42@gmail.com>
To: linux-sunxi@googlegroups.com
Cc: Marcus Weseloh <mweseloh42@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Chen-Yu Tsai <wens@csie.org>,
	linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2] spi: sun4i: Prevent chip-select from being activated twice before a transfer
Date: Tue,  5 Jan 2016 21:46:20 +0100	[thread overview]
Message-ID: <1452026780-8819-1-git-send-email-mweseloh42@gmail.com> (raw)

The SPI core calls set_cs before a transfer, but the SUN4I_CTL_CS_MANUAL
flag is only set in transfer_one. This leads to the following pattern on
the chip-select line (with runtime power-management on every transfer,
without it only on the first one):

activate, deactivate, activate, transfer, deactivate

Moving the configuration of the SUN4I_CTL_CS_MANUAL flag from transfer_one
to set_cs removes the double activation.

Signed-off-by: Marcus Weseloh <mweseloh42@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---

Changes from v1:
- Added Maximes Acked-by

---

 drivers/spi/spi-sun4i.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
index fbb0a4d..a6d936c 100644
--- a/drivers/spi/spi-sun4i.c
+++ b/drivers/spi/spi-sun4i.c
@@ -140,6 +140,9 @@ static void sun4i_spi_set_cs(struct spi_device *spi, bool enable)
 	reg &= ~SUN4I_CTL_CS_MASK;
 	reg |= SUN4I_CTL_CS(spi->chip_select);
 
+	/* We want to control the chip select manually */
+	reg |= SUN4I_CTL_CS_MANUAL;
+
 	if (enable)
 		reg |= SUN4I_CTL_CS_LEVEL;
 	else
@@ -222,9 +225,6 @@ static int sun4i_spi_transfer_one(struct spi_master *master,
 	else
 		reg |= SUN4I_CTL_DHB;
 
-	/* We want to control the chip select manually */
-	reg |= SUN4I_CTL_CS_MANUAL;
-
 	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
 
 	/* Ensure that we have a parent clock fast enough */
-- 
1.9.1


WARNING: multiple messages have this Message-ID (diff)
From: Marcus Weseloh <mweseloh42-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
Cc: Marcus Weseloh
	<mweseloh42-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Maxime Ripard
	<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH v2] spi: sun4i: Prevent chip-select from being activated twice before a transfer
Date: Tue,  5 Jan 2016 21:46:20 +0100	[thread overview]
Message-ID: <1452026780-8819-1-git-send-email-mweseloh42@gmail.com> (raw)

The SPI core calls set_cs before a transfer, but the SUN4I_CTL_CS_MANUAL
flag is only set in transfer_one. This leads to the following pattern on
the chip-select line (with runtime power-management on every transfer,
without it only on the first one):

activate, deactivate, activate, transfer, deactivate

Moving the configuration of the SUN4I_CTL_CS_MANUAL flag from transfer_one
to set_cs removes the double activation.

Signed-off-by: Marcus Weseloh <mweseloh42-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Acked-by: Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
---

Changes from v1:
- Added Maximes Acked-by

---

 drivers/spi/spi-sun4i.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
index fbb0a4d..a6d936c 100644
--- a/drivers/spi/spi-sun4i.c
+++ b/drivers/spi/spi-sun4i.c
@@ -140,6 +140,9 @@ static void sun4i_spi_set_cs(struct spi_device *spi, bool enable)
 	reg &= ~SUN4I_CTL_CS_MASK;
 	reg |= SUN4I_CTL_CS(spi->chip_select);
 
+	/* We want to control the chip select manually */
+	reg |= SUN4I_CTL_CS_MANUAL;
+
 	if (enable)
 		reg |= SUN4I_CTL_CS_LEVEL;
 	else
@@ -222,9 +225,6 @@ static int sun4i_spi_transfer_one(struct spi_master *master,
 	else
 		reg |= SUN4I_CTL_DHB;
 
-	/* We want to control the chip select manually */
-	reg |= SUN4I_CTL_CS_MANUAL;
-
 	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
 
 	/* Ensure that we have a parent clock fast enough */
-- 
1.9.1

WARNING: multiple messages have this Message-ID (diff)
From: mweseloh42@gmail.com (Marcus Weseloh)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] spi: sun4i: Prevent chip-select from being activated twice before a transfer
Date: Tue,  5 Jan 2016 21:46:20 +0100	[thread overview]
Message-ID: <1452026780-8819-1-git-send-email-mweseloh42@gmail.com> (raw)

The SPI core calls set_cs before a transfer, but the SUN4I_CTL_CS_MANUAL
flag is only set in transfer_one. This leads to the following pattern on
the chip-select line (with runtime power-management on every transfer,
without it only on the first one):

activate, deactivate, activate, transfer, deactivate

Moving the configuration of the SUN4I_CTL_CS_MANUAL flag from transfer_one
to set_cs removes the double activation.

Signed-off-by: Marcus Weseloh <mweseloh42@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---

Changes from v1:
- Added Maximes Acked-by

---

 drivers/spi/spi-sun4i.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
index fbb0a4d..a6d936c 100644
--- a/drivers/spi/spi-sun4i.c
+++ b/drivers/spi/spi-sun4i.c
@@ -140,6 +140,9 @@ static void sun4i_spi_set_cs(struct spi_device *spi, bool enable)
 	reg &= ~SUN4I_CTL_CS_MASK;
 	reg |= SUN4I_CTL_CS(spi->chip_select);
 
+	/* We want to control the chip select manually */
+	reg |= SUN4I_CTL_CS_MANUAL;
+
 	if (enable)
 		reg |= SUN4I_CTL_CS_LEVEL;
 	else
@@ -222,9 +225,6 @@ static int sun4i_spi_transfer_one(struct spi_master *master,
 	else
 		reg |= SUN4I_CTL_DHB;
 
-	/* We want to control the chip select manually */
-	reg |= SUN4I_CTL_CS_MANUAL;
-
 	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
 
 	/* Ensure that we have a parent clock fast enough */
-- 
1.9.1

             reply	other threads:[~2016-01-05 20:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-05 20:46 Marcus Weseloh [this message]
2016-01-05 20:46 ` [PATCH v2] spi: sun4i: Prevent chip-select from being activated twice before a transfer Marcus Weseloh
2016-01-05 20:46 ` Marcus Weseloh
     [not found] ` <1452026780-8819-1-git-send-email-mweseloh42-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-01-08 13:44   ` Applied "spi: sun4i: Prevent chip-select from being activated twice before a transfer" to the spi tree Mark Brown

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